Alder Creek Restoration Project
Sauvie Island, OR

For a restoration project on Sauvie Island, Turnstone provided consulting services to assist with the creation of a mitigation bank prospectus. Turnstone analyzed existing and proposed elevations to determine the amount of wetland and tidal water mitigation credits that could potentially be generated by the site. This was done by analyzing historic maps and records and comparing it to proposed post-construction elevations. Turnstone conducted a number of ORWAP functional assessments to support the proposal. Turnstone classified wetlands and waters on the site using the HGM and Cowardin classifications. Turnstone defended an ecological basis for the service area as opposed to the typical HUC4 watershed typically used. Turnstone provided a description of the proposed physical, chemical, and biological characteristics of the site and how the site would support the planned types of aquatic resources and functions. Turnstone addressed the functional gains of the proposed stream work and how the gains are similar or preferable to the functions and values of the aquatic habitats expected to be lost in the watershed. Turnstone staff also conducted baseline wildlife monitoring, including eagle and raptor surveys, point count surveys, mink sign surveys, and wildlife camera monitoring. During the construction phase of the project, Turnstone staff conducted turbidity monitoring to ensure compliance with NOAA and DSL permit conditions.